Jantz et al. reply —

We appreciate the points made by Feeley and Rehm and we recognize that a network of well-connected protected areas could be extremely valuable for preserving biodiversity in the context of increasingly intense land use and climate change. It is clear that the increasing isolation of protected areas is exacting a toll on tropical species1.

We agree that focusing on vegetation carbon stocks (VCS) alone cannot be expected to result in conservation corridors that are optimal for movement, migration and the dispersal of specific species. This was not, however, the primary objective of our research2. Instead, we focused primarily on investigating the potential for biodiversity co-benefits in the context of tropical emissions avoidance policies that consider not only deforestation and VCS, but also the contiguity of carbon stocks. Carbon finance is one of the most promising instruments for conserving existing forest habitat outside of parks and protected areas. Directing funds in a systematic manner, such as we describe via a network of corridors, could undoubtedly be a policy option for maintaining or even restoring continuous habitats while also preventing or mitigating habitat fragmentation — a process that threatens species viability, particularly under climate change.

The degradation of carbon stocks over time due to edge effects is a potential risk, and may happen in narrow corridors, but in many cases we expect the opposite to occur. Forests will regrow in degraded areas, on abandoned slash-and-burn agriculture landscapes and between existing forest fragments. All of these areas exist within our corridor network, and they offer the best solution for connecting protected areas. There is enormous potential to use these areas to our collective advantage, by allowing forests to regrow where they are most needed for biodiversity while sequestering atmospheric carbon in the process — another benefit of the corridor approach we propose. Moreover, allowing this process to occur in riparian forests, where many of our corridors are located, has the additional benefit of protecting water resources and associated aquatic biodiversity.

We also agree that connecting similar habitat types is preferable in most circumstances. This will typically be the case as we consider nearest-neighbour protected areas in a pairwise fashion. However, where the spatial turnover of habitat is high, homogenous corridors will not always be achievable. While species will disperse more readily through their preferred habitat, they may still disperse through similar intervening habitats, making corridors that traverse multiple habitats valuable for conservation. Indeed, a variety of corridor types will likely be necessary to maintain tropical biodiversity in the coming decades. Those that connect the same habitat types and those that connect habitats across environmental gradients can both facilitate species movement under climate change while also avoiding deforestation and forest degradation outside of protected areas.

There are many applications for these corridors and many ways that they can be improved and considered for use in various management contexts. To that end, we have made the data freely accessible (www.whrc.org/corridors).

We encourage the exploration and assessment of corridor utility in the context of national, regional and local land-use priorities and forest conservation activities, as well as in the broader context of REDD+ implementation. We also welcome feedback on their utility for these applications and on the ways that they can be improved.